THE CATKINS OF THE WILLOW 



comes it, then, that the flowers of the willow 

 catkins secrete nectar to attract insects ? Un- 

 doubtedly the willows were once wind-fertilised, 

 as the complete absence of a corolla or floral 

 envelope and the simple structure of their flowers 

 plainly indicate ; but, probably owing to bees and 

 other insects showing great appreciation for their 

 pollen and frequently visiting their flowers in 

 search of it, the flowers have again produced 

 nectar. I say ^' again produced nectar" advisedly, 

 because I have, in an earlier chapter, already ex- 

 pressed the opinion that the remote ancestors of 

 wind-fertilised flowers once wooed insects with 

 nectar and coloured floral parts, but that they had 

 now changed their habit ; therefore, I suggest that 

 the willows have again returned to insect-fertili- 

 sation. 



However, having once lost their petals and 

 other floral parts, they could not again repro- 

 duce these. Nectar has once more been pro- 

 vided, but not necessarily from the same nectaries 

 that the original insect-fertilised flowers possessed ; 

 most likely these nectaries are an entirely new 

 and much later development, evolved as a means 

 of saving the pollen that was being carried away 

 by the bees for their own use ; for nectar is 

 cheaper to produce than rich pollen, and probably 

 owes its origin generally to that reason. The 

 coloured envelopes having been aborted, all the 

 male flowers can do in the colour direction is to 

 make their stamens as attractive as possible ; and 

 the female flowers can only develop the silky hairs 



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